Hub-mounted, slit-elastic needle guard

ABSTRACT

Intravenous needle sheaths are described which can be used safely for exposing the recapping the sharp tips. The sheaths comprise partially slit concentric or eccentric elastic tubes with special markings, the proximal ends of which are anchored permanently to the hubs of various kinds of needles, and the distal ends of which guide the tips safely through combinations of rigid and elastic parts in all positions of needle exposure, use and resheathing.

BACKGROUND OF THE INVENTION

1. Field of the Invention.

The invention relates to permanently attached needle guards or sheaths.

2. Description of the Prior Art.

contaminated blood from infected persons is a common source of HIV andHBV virus infecitions in health care workers. (See Morbidity andMorality Weekly Report, Jun, 24, 1988, Vol. 37 No. 24, pp. 377-388).Infection control must focus on needle safety, the appropriate use ofgloves and immunizations whenever available. Although aseptic proceduresand gloves protect such workers, these cannot uniformly preventneedle-stick injuries with contaminated blood.

Needles and needle/syringe combinations are now almost routinelysheathed in tapered or non-tapered, closed or open end, rigid plasticsheaths which are discarded after the needle is exposed. After use, noattempt is made to resheath the needle because too many needle-stickinjuries result. Instead, the needles, butterfly assemblies, infusionsets, syringe/needle combinations or double-ended needles fromvacutainer systems are disposed as soon as possible into rigid safetycontainers which may, or may not, be readily available.

The accordion needle sheath developed by Peters in Great Britain anddescribed in International Patent Application Number: PCT/GB86/00194filed 8 Apr., 1986, has not achieved popular use, apparently for threereasons:

(a) it is relatively expensive to manufacture, owing to the complexityand possible slippage of parts;

(b) the elastic components of the system theoretically work againstresheathing the needle; and

(c) the user muse use his fingers perilously close to the tip of theneedle to sheath or resheath.

A slit, but rigid and hinged plastic sheath developed in Sweden (SwedenApplication Number 8505880-8 filed Dec. 12, 1985) has not achievedpopular use, apparently for two reasons:

(a) proximal attachment of the slit sheath would require too manymodifications of standard needle hubs, thus precluding manufacture inquantity for all kinds of needles or needle/syringe assemblies.

(b) when unhinged, the sheath might be awkward to use especially withbutterfly and vacutainer systems.

The instant invention combines the elasticity of the durable elastomerictubing now available with the slit by means of which one can expose orresheath the needle, to form a permanently tethered needle sheath whichis an inexpensive, adjunct to needle safety wherever rigid steel needlesare employed to withdraw blood or give injections, especially intoveins.

This invention relates to permanently tethered needle sheaths made ofelastic and rigid materials through which slits are made to expose andsafely resheath hollow needles used for drawing blood or administeringintravenous medications. One object of this invention is to provide aneedle guard which will minimize the risk of "needle-stick" injuries tomedical personnel and other persons after blood specimens or tissuefluids potentially containing infections agents, especially AIDS andserum hepatitis viruses, have been withdrawn from individuals requiringtests or treatment. A further object of this invention is to provide auseful, safer needle sheathing system which can be produced at minimalcost to the manufacturer, as well as the user.

SUMMARY OF THE INVENTION

Needle sheaths are described which can be safely used to expose andresheath hollow intravenous needles. The sheaths comprise partially slitelastic tubes, the proximal ends of which are anchored permanently tothe needle hubs, while the distal ends contain rigid plastic sleeves tosafely house the sharp tips when the needles are not in use. Beyond therigid sleeves, which may be capped or uncapped, the elastic tubingextends beyond the tip of the needle to allow easy and safe manipulationof the assembly during needle exposure, use for injections or drawingblood and immediate resheathing of the needle.

An outstanding safety feature is that there is substantially no lag timeafter the user withdraws the needle from the vein of a subject until theneedle is capped. As soon as he/she lets go of the tip of the elastictube, the tube immediately and automatically recoils back into place forresheathment of the entire needle. Gentle traction at the distal end ofthe assembly rehouses the needle tip within its rigid puncture-proofhousing. Subsequently, the needle, tubing, syringe or double-tippedvacutainer needle can be transported to the nearest safe container withminimal chance of straight on or tangential needle-stick injury to theuser or anyone located nearby.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1: A cutaway schematic view of the intravenous needle sheath of thepresent invention protecting a standard needle (left) or butterflyneedle (right).

FIG. 2: A schematic representation of the sheath of FIG. 1 opening toexpose the needle tip.

FIG. 3: A schematic view of the needle sheath of FIG. 1 with the sheathfolded back to expose the entire needle. During needle insertion into avein, the tip of the sheath is grasped between the closed wings ofbutterfly needles, or alongside the barrels of syringes and vacutainersystems, as depicted below.

FIG. 4: A magnified cutaway view of the positioning of the rigid plasticcap or sheath housed within the elastic tubing relative to the slit, therigid portion and the needle tip.

FIG. 5: An alternative version wherein the rigid inner sheath is notcapped, but extended beyond the potential projection of needle if theassembly is collapsed toward the needle hub.

FIG. 6: A cross section through a concentric elastomeric tube at thelevel of the slit of a first preferred embodiment.

FIG. 7: A cross section through an eccentric elastomeric tube at thelevel of the slit in a second preferred embodiment.

FIGS. 8 (a,b,c): Action drawing showing the first preferred embodimentbeing used to expose a needle prior to use.

DESCRIPTION OF THE PREFERRED EMBODIMENT A. First Preferred Embodiment

The hypodermic needle sheath comprising the first preferred embodimentof the present invention can best be understood by looking first atFIG. 1. The sheath comprises a single section of elastomer tubing havinga proximal end (13) permanently effixed to a needle hub (14) and adistal end (11). Interposed within the lumen of the tubing is aprotective cap (12) positioned to cover the tip of the needle when thesheath is closed (FIG. 4). A slit (15) in the proximal segment of thesheath tubing (13) permits the sheath to be removed from the needle by(a) applying gently tension on the distal end of the sheath and (b)bending the sheath so that the needle emerges through the slit (15) asshown schematically in FIG. 2 and FIG. 3. The needle tip may be recappedby reversing the procedure. Due to the elasticity of the proximal end ofthe sheath (13) when the distal end is released as a prelude tosheathing the needle, the sheath will assume as position substantiallyparrallel to the needle. Gentle tension on the distal end (11) permitsthe needle to be guided through the slit (15) into the interior lumen ofthe sheath. Relaxing the tension on the distal end completes theresheathing by seating the needle tip safely within the interior of theprotective cap (12). The above sequence of motions required for exposinga needle is shown in FIG. 8. Resheathing the needle is accomplished byreversing the steps.

B. Second Preferred Embodiment

A second preferred embodiment is similar to the first except that theprotective cap (12) is open on both ends (FIG. 5). Since the proximalend of the sheath (12) is not compressible, a needle sheath with thisprotective cap is resistant to straight-on needle pricks and immune totangential needle pricks.

C. Other Perferred Embodiments

During needle use, the normal position for the sheath is bent back awayfrom the needle and secured in position by restraining means. When theneedle is withdrawn from a patient and is desirably resheathed, therestraint securing the sheath in the bent-back position is removed andthe sheath snaps back against the needle thus providing a degree ofimmediate protection against accidental needle pricks. It is desirablethat the elasticity of the proximal end of the needle protective cap besufficient to hold the sheath snugly snugly against the needle. Theelasticity of the sheath in either of the first two embodiments may beimproved still further by differentially reinforcing the wall on theproximal end of the sheath (13) on the side opposite the slit as shownin FIG. 7. FIG. 6 shows the proximal end of the sheath tubing wherein aconcentric wall surrounds the needle (19) whereas the tubing of FIG. (7)presents an eccentric wall about the needle.

The foregoing embodiments are provided to instruct in the use of theinvention. The scope of the invention is not limited to the particularembodiment described above.

What I claim is:
 1. A needle sheath for preventing accidental needlesticks comprising: (a) an elastomer tube containing a lumen ofsufficient size to house a needle within said lumen, one end of saidtube being concentrically affixed to the hub of said needle; and (b) ahollow substantially cylindrical protective cap containing an interiorchamber, said protective cap being permanently disposed within saidlumen of said tube such that the sharp tip of said needle is within ininterior chamber of said protective cap when said needle is sheathedthereby protecting the needle user from end-on accidental needle sticks;and (c) a slit in the wall of said tube, the direction of said slitbeing parallel to said lumen and extending substantially from saidprotective cap to said needle hub to permit passage of said needlethrough the wall of said tube when said tube is extended.
 2. The sheathof claim 1 wherein said protective cap is made of a material resistantto puncture by a hypodermic needle.
 3. The sheath of claim 2 whereinsaid elastomeric tube is silicone.
 4. The sheath of claim 2 wherein saidelastomeric tube is latex.
 5. The sheath of claim 2 wherein saidelastomeric tube is polyethylene.
 6. The sheath of claim 2 wherein thelength of said slit is 50-95% of the length of said needle.
 7. Thesheath of claim 2 further comprising an optically visibleslit-delineating marker on the wall of said tube contiguous with saidslit.
 8. A needle sheath comprising (a) a substantially cylindricalprotective cap to protect a user from accidental end-on needle stickinjury, said cap containing an open end and a closed end, the open endof said cap being permanently affixed to a length of elastomeric tubing,said tubing having a longitudinal slit wall extending substantiallyparrallel to the long axis of said tubing, said slit providing means topermit exposure of a hypodermic needle contained within the lumen ofsaid tubing; and (b) a tab providing means for grasping said sheathaffixed to the closed end of said protective cap.
 9. The sheath of claim8 in which said elastomeric tubing is silicone.
 10. The sheath of claim8 in which said elastomer tubing is polyethylene.
 11. The sheath ofclaim 8 in which said elastomer tubing is latex.
 12. The sheath of claim8 wherein the length of said slit is 50-95% of the length of the needle.13. The sheath of claim 8 wherein said tub is an extension of saidelastomeric tubing, said extension being of sufficient length toprotrude 1-3 inches beyond the closed end of said protective cap. 14.the sheath of claim 8 further comprising an optically visibleslit-delineating stripe on the wall of said elastomer tubing parallel toand contiguous with said slit.
 15. A permanently anchored tubularelastic needle sheath for minimizing the chances of needle-stick injury,comprising:(a) a hollow elastic tube having a proximal end firmlyattachable to the hub assembly surrounding a needle used for drawingblood or giving an injection; (b) a longitudinal slit in the wall ofsaid tube, said slit being in a direction parallel with the long axis ofsaid tube, said slit providing an opening through which the needle isexposed when the elastic tube is stretched and swung away; (c) a distalend significantly longer than the needle, providing means for manuallygrasping the needle sheath to unsheath and resheath the needle by gentlemanual traction in vectors closely aligned. with the long axis of theneedle.